Magneto accelerator



Feb. 26 9 1 924. I 1,485,014

7 s. B. BOOTY MAGNET 0 ACCELERATOR Filed Feb.- 2451921 L STu ufl B. BooTy b ATTys Patented Feb. 26, 1924.

UNITED STATES PATENT QFFECE;

STUART BER/TEAM BOOTY, OF EAST PERTH, WESTERN AUSTRALIA, AUSTRALIA, AS-

SIGNOR 0F ONE-HALF TO JAMES ABSALOM TURNER, OF PERTH, WESTERN AUS- TRALIA, AUSTRALIA.

m Gnn'ro ACCELERATOR.

Application filed February 24, 1921. Serial No. 447,605.

I '0 all whom it may concern:

Be it known that I, STUART BERTRAM Boorr, a subject of the King of Great Britain and Ireland, residing at 69. Moore Street, East Perth, Western Australia, in the Commonwealth of Australia, have invented new and useful Improvements in Magneto Accelerators, of which the following is a specification.

This invention relates to an improved magneto accelerator, that is to say, it re lates to an apparatus for giving a rapid rotary impulse to the magneto spindle, thereby producing an intensely hot spark.

It is well known that the cranking up to start internal combustion engines is frequently a difficult operation often requiring several attempts before the engine fires. This difficulty is caused through the spark produced by the magneto not being hot enough to ignite the mixture. Even when a self starter is used the starting motor must usually rotate some little time before it acquires a speed sufficient to cause the magneto to give a spark of the required temperature and this means that the life of the batteries supplying current to the motor is much shorter than if the engine started ahnost at once.

Means have previously been devised having for their object to give the magneto spindle a very rapid acceleration almost immediately after commencing to turn the crank or in the case of a self starter after the motor commenced to drive and consequent upon such rapid acceleration immediately producing a very hot spark which ignited the mixture and so started the engine.

In practical operation, however, the aforesaid means, have either not given the desired accelerating impulse to the magneto spindle or else have been defective in that the accelerating means have from time to time accidentally fallen into gear when the magneto is revolving at a high rate of speed, with of course, disastrous results to the apparatus.

Now the primary object of the present invention is to provide means whereby the accelerating device is readily thrown into action when it is desired to start the motor and is thrown and positively kept out of action when the accelerating impulse has been given.

understood I will now refer to the accomit occupies before attempting to startthe neto drive shaft. tached to the magneto body and this plate member, the other end of which is formed as a cam. Vhen the pawl is thrown out of engagement with the magneto spindle itis held out of engagement through the medium of the cam end of the said member.

To enable the invention to be more readily panying wl1erein I I v Fig. 1 shows an elevation. of the apparatus partly: in section and in the position sheet of explanatory drawings engine. v V 1 Fig. 2 also shows an elevation partly'jin section but having the parts in the relative position they will occupy justbeforethe accelerating impulse is given, and I Fig. 3 is a plan. of the pawland cam member.

In the drawings, the magneto spindle 10 has keyed thereto a'sleeve 11 formed integral withwhich is a disc 12 formed with an upright stop 14 and also. having, two notches 13 cut therein. Turning loosely on the collar 11 is a driving member in the form of a spring barrel 15 the channel 16 of which at one part is formed with a stop 17. The barrel 15 also has two lugs or cams 18 oppositely disposedon the outside thereof and also screw holes 19 for attaching to a flange or the like on to the mag- A metal plate 20 is athas attached a pivot on which turns member one end 22 of which acts as a pawl whilst the other'end acts as a cam. The

working face of the said pawl is cutaway.

slightly at 23 so as to give an overhanging portion 24 of the pawl which is the portion actually struck by the lugs or cams 18. The cam end of the member is cut awayto afford clearance for the lower end" of a control lever 25 and it is formed with two faces 26 and 27 and of these faces the face 27 is further from the pivot 21 on which. the

. member turns. The control lever 25 is pivoted at 28 and to it isattached a pin 29 connected to which is one end of a tensional spring the other end of which is attached to a similar pin 30 on the pawl'and cam member a little above the pivot 21. A stop 31 is attached to the plate 20 so as to limit the anti-clockwise movement of the control lever 25.

The operation of the apparatus is as follows z-lVhen it is desired to start the engine the control lever 25 is turned in a clockwise direction and held preferably by a cord, thereby throwing the pawl 22 into the path of the notches 13 one of which it will subsequently engage. The crank is then turned whereby a torque is applied to the spring barrel 15 (through the screw holes 19) with the result that the stop 17 compresses one end of the spring the other end of which presses against the stop 14 of the disc and so tries to turn the magneto spindle being prevented however by the pawl 22 holding a notch 13. The result is that the barrel 15 commences to turn against the compression of the spring until a lug or cam 18 reaches the. pawl and acting on the face 2a thereof throws it out of engagement with the notch 13. The disc 12 is thereby released and the kinetic energy stored in the compressed spring gives a very strong accelerating im pulse thereto (and consequently to the attached magnet spindle) turns the magneto armature rapidly over the ignition point and so causes explosion of the mixture. \Vhen the disc 12 has been turned by the spring around to its normal position relatively to the spring barrel it continues to be driven by its stop 14 being continuously pressed by the spring.

lVhen the pawl is thrown out of engagement with a notch by one of the lugs 18 the cam face 26 is pulled by a spring against the pin 29, and as the cam face 27 is further from the pivot 21 than the face 26 it will be necessary to stretch the spring if the member is to turn back so as to again throw the pawl into the path of the notch. The result of this construction is that the pawl is precluded from accidentally moving into engagement with a notch although it readily turns in when the control lever is turned and moves the pin 29 away from the cam face 26 and simultaneously pulls the spring.

I claim 1. In a device of the'character described, the combination with a notchedmember adapted to be attached to a magneto spindle. of a pawl member pivoted intermediate of its ends and having at one end a pawl adapted to be moved into engagement with the notched member thereby to prevent it from turning, the opposite end of said pawl member having a cam face, a driving member adapted to be connected to the magneto shaft, a spring connection between said driving member and notched member, a spring connected to the pawl member and co-operating with the cam face to hold the pawl normally out of engagement with the notched member, means co-operating with said spring by which the pawl member is thrown into operative position and means to disengage the pawl from the notched member.

2. In a device of the character described, the combination with a notched member adapted to be attached to a magneto spindle, of a pawl member pivoted intermediate of its ends and having at one end a pawl adapted to engage said notched member thereby to prevent it from turning, the opposite end of said pawl member having a cam face, a driving member adapted to be connected to the magneto shaft, a spring connection between said driving'member and notched member, a spring connected to the pawl member, movable means co-operating with said spring and cam face for hnlding the pawl normally in inoperative position out of engagement with the notched member, movement of said means operating through the spring to move the pawl into operative position in engagement with the notched member, means co-operating with the cam face on the pawl member to hold the pawl in such operative position, and means to disengage the pawl from the notched member by movement of the driving member.

:3. In a device of the character described, the combination with a notched member adapted to be attached to a magneto spindle, of a pawl member pivoted intermediate of its ends and having at one end a pawl normally out of engagement with the notched member but adapted to be moved into engagement therewith thereby to prevent it from turning, the opposite end of said pawl member having a cam face, a driving member adapted to be connected to the magneto shaft, a spring connection between said driving member and notched member, a spring connected to the pawl member, means co-operating with said spring by which the pawl. member is thrown into operative position, said means adapted to hold the pawl either in operative or inoperative position, and means to disengage the pawl from the notched member by movement of the driving member.

4:. In a device of the class described, the combination with a notched member adapted to be attached to a magneto spindle, of a pawl member pivoted intermediate of its ends and having at one end a pawl adapted to engage the notched member and prevent it from turning, the opposite end of said pawl member having two cam faces, a rotary driving member having a cam, a spring forming a driving connection between the driving member and the notched member, a pivoted controlling lever having a portion to engage the cam faces of the pawl member, and a spring connecting the pawl member to the controlling lever, whereby in one position of the lever the spring connected to the pawl member oooperates with the controlling lever and one cam face to hold the pawl member in inoperative position, and another position of the controlling lever said spring oo-operates with the pawl member and the other cam face to hold the pawl member in operative position.

5. In a device of the class described, the combination with a notched disc adapted to be keyed to a magneto spindle, of a spring barrel loosely surrounding said spindle and adapted to be connected to a magneto driving shaft, a spring forming a driving connection between the spring barrel and the notched disc, a pawl member pivoted intermediate of its two ends and having one end formed as a pawl to engage said notched disk and having the other end formed with a cam face, a movable pin operating against said cam face, a spring connecting said pin with the pawl member and means to disengage the pawl from the notched disc by the rotation of the spring barrel.

6. In a device of the class described, the combination with a notched disc connected to a magneto spindle, of a spring barrel loosely surrounding said spindle and adapted to be connected to the magneto driving shaft, a cam on the spring barrel, a spring forming a driving connection between said spring barrel and notched disc, a pawl member pivoted intermediate of its two ends and having one end formed as a pawl to engage said notched disc and the other end provided with a cam face, a pivoted control lever, a pin connected to the said control lever and working against said cam face, a spring connecting the aforesaid pin with the cam member, and means to disengage the pawl from the notched disc by the rotation of the spring barrel.

Dated this fifteenth day of January, 1921.

STUART BERTRAM BOOTY. 

